In 1996, the U.S. began restructuring its Ballistic Missile Defense (BMD) to a scaled-back version of the space-based Strategic Defense Initiative "Star Wars" program proposed by President Reagan in 1993.
The U.S. signed an Anti-Ballistic-Missile treaty with the Soviet Union in 1972 but wants to modify that treaty to develop defenses against attacks by rogue states such as Iran and North Korea.
In May 2000, Russian President Putin warned that if the U.S. withdraws from the 1972 Treaty, Russia would withdraw from the START II Treaty and from the whole system of treaties on limitation and control of strategic and conventional weapons.
Arms control specialists fear this might compel China to expand and modernize their missile program and that a chain reaction of nuclear weapons proliferation including India and Pakistan could ensue.
Cost of a system with 100 missile interceptors at a single site in Alaska is estimated to be $36 billion, $60 billion for two.
By March 1999, during the first phase of development, all six test attempts to hit a flying target failed.
The first successful test was in June 1999, followed by a successful test involving a separated warhead outside the earth's atmosphere in August.
Two tests in January and August 2000 failed.
A study by MIT and the Union of Concerned Scientists in 2000 concluded that the proposed BMD system could be easily fooled by simple decoys or other countermeasures.
A British committee urged the U.S. to seek other ways of reducing the perceived threats.
